A preliminary assessment of the geochemical dynamics of Issyk‐Kul Lake, Kirghizstan

Abstract

Issyk‐Kul Lake is one of the largest brackish water lakes in the world. Being a closed‐basin lake, it is susceptible to volume changes caused by natural climatic variability, as well as human‐induced water diversion from the basin. Long‐term lake level records indicate that lake levels are declining and that salinity is increasing because of evapoconcentration. We present the first trace element data for this important lacustrine system and, using both ours and previously published data, investigate the geochemical dynamics within the watershed.

Atmospheric noble gases in lake sediment pore water as proxies for environmental change

“…(ii) The salinity S ( h ) is inversely proportional to the volume of the water body V ( h ) (as given by Tsigelnaya [1995]), i.e., the total mass of dissolved salt in the lake is assumed constant. This assumption is justified because the residence time of the major solutes in the lake is about 30 kyr or more [ Tsigelnaya , 1995; Lyons et al , 2000]. (iii) The water temperature at the sediment surface is also assumed to depend on water level because the distance from sediment to lake surface decreases with decreasing water level.…”

Rapid deep‐water renewal in Lake Issyk‐Kul (Kyrgyzstan) indicated by transient tracers

“…The lake has no outflow and a refill time of ϳ330 yr. Precipitation over the lake surface is 277 mm yr Ϫ1 , and surface inflow corresponds to 568 mm yr Ϫ1 (Tsigelnaya 1995). The salinity (S) of the lake water is ϳ6‰ (the chemical composition is given by Tsigelnaya 1995 andLyons et al 2001). January mean air temperatures at the lake are below Ϫ2ЊC (Adyshev et al 1987), but Lake Issyk-Kul never freezes completely.…”